Internet of Things (IoT) devices have become popular in home environments. They provide various sensed data and make it possible to act on control systems to facilitate proper environmental welfare. This paper presents an architecture based on digital twins for integration into the Home Assistant platform, oriented to the automatic management of environmental sensors in smart home environments. The solution is applied to indoor air quality monitoring to preserve the well-being of home occupants. To this end, an infrastructure capable of virtually representing each physical sensor deployed is proposed, allowing it to maintain its functionality even in the event of communication failures or temporary disconnection of the actual sensors. In addition, the article proposes an environmental welfare model, which evaluates the adequacy of the measured values through a welfare index per room. The proposed model allows discriminating between normal, moderate or critical situations, triggering the necessary actions to restore the ideal conditions or alerting to possible sensor failures. A use case shows the functioning of the system.